Regional clustering of shared neutralization determinants on primary isolates of clade C human immunodeficiency virus type 1 from South Africa

Clade C is one of the most prevalent genetic subtypes of human immunodeficiency virus type 1 (HIV-1) in the world today and one of the least studied with respect to neutralizing antibodies. Most information on HIV-1 serology as it relates to neutralization is derived from clade B. Clade C primary isolates of HIV-1 from South Africa and Malawi were shown here to resemble clade B isolates in their resistance to inhibition by soluble CD4 and their sensitivity to neutralization by human monoclonal antibody immunoglobulin G1b12 and, to a lesser extent, 2F5. Unlike clade B isolates, however, all 16 clade C isolates examined resisted neutralization by 2G12. Infection with clade C HIV-1 in a cohort of female sex workers in South Africa generated antibodies that neutralized the autologous clade C isolate and T-cell-line-adapted (TCLA) strains of clade B. Neutralization of clade B TCLA strains was much more sensitive to the presence of autologous gp120 V3 loop peptides compared to the neutralization of clade C isolates in most cases. Thus, the native structure of gp120 on primary isolates of clade C will likely pose a challenge for neutralizing antibody induction by candidate HIV-1 vaccines much the same as it has for clade B. The autologous neutralizing antibody response following primary infection with clade C HIV-1 in South Africa matured slowly, requiring at least 4 to 5 months to become detectable. Once detectable, extensive cross-neutralization of heterologous clade C isolates from South Africa was observed, suggesting an unusual degree of shared neutralization determinants at a regional level. This high frequency of cross-neutralization differed significantly from the ability of South African clade C serum samples to neutralize clade B isolates but did not differ significantly from results of other combinations of clade B and C reagents tested in checkerboard assays. Notably, two clade C serum samples obtained after less than 2 years of infection neutralized a broad spectrum of clade B and C isolates. Other individual serum samples showed a significant clade preference in their neutralizing activity. Our results suggest that clades B and C are each comprised of multiple neutralization serotypes, some of which are more clade specific than others. The clustering of shared neutralization determinants on clade C primary HIV-1 isolates from South Africa suggests that neutralizing antibodies induced by vaccines will have less epitope diversity to overcome at a regional level.

Factors, enablers and challenges for COVID-19 vaccine development

The COVID-19 pandemic triggered a sense of vulnerability and urgency that led to concerted actions by governments, funders, regulators and industry to overcome traditional challenges for the development of vaccine candidates and to reach authorisation. Unprecedented financial investments, massive demand, accelerated clinical development and regulatory reviews were among the key factors that contributed to accelerating the development and approval of COVID-19 vaccines. The rapid development of COVID-19 vaccines benefited of previous scientific innovations such as mRNA and recombinant vectors and proteins. This has created a new era of vaccinology, with powerful platform technologies and a new model for vaccine development. These lessons learnt highlight the need of strong leadership, to bring together governments, global health organisations, manufacturers, scientists, private sector, civil society and philanthropy, to generate innovative, fair and equitable access mechanisms to COVID-19 vaccines for populations worldwide and to build a more efficient and effective vaccine ecosystem to prepare for other pandemics that may emerge. With a longer-term view, new vaccines must be developed with incentives to build expertise for manufacturing that can be leveraged for low/middle-income countries and other markets to ensure equity in innovation, access and delivery. The creation of vaccine manufacturing hubs with appropriate and sustained training, in particular in Africa, is certainly the way of the future to a new public health era to safeguard the health and economic security of the continent and guarantee vaccine security and access, with however the need for such capacity to be sustained in the interpandemic period.

Conserved domains of subtype C nef from South African HIV type 1-infected individuals include cytotoxic T lymphocyte epitope-rich regions

We have characterized 43 nef sequences from subtype C HIV-1-infected South Africans and compared deduced amino acid sequences with other subtypes to identify areas of conservation. Our Nef amino acid sequences were aligned with a consensus subtype B, HXB2 reference strain and a consensus subtype C sequence. All were found to be highly homologous to subtype B in the central region of Nef, but more variable at the N and C termini of the molecule. Alignment of a consensus amino acid sequence generated from South African subtype C Nef with subtypes A, B, and D underscores cross-clade conservation in the central domain of the molecule. This domain is also rich in previously described cytotoxic T lymphocyte (CTL) epitopes that are restricted by commonly found HLA molecules in the South African population.

High mortality rates in men initiated on anti-retroviral treatment in KwaZulu-Natal, South Africa

In attaining UNAIDS targets of 90-90-90 to achieve epidemic control, understanding who the current utilizers of HIV treatment services are will inform efforts aimed at reaching those not being reached. A retrospective chart review of CAPRISA AIDS Treatment Program (CAT) patients between 2004 and 2013 was undertaken. Of the 4043 HIV-infected patients initiated on ART, 2586 (64.0%) were women. At ART initiation, men, compared to women, had significantly lower median CD4+ cell counts (113 vs 131 cells/mm3, p <0.001), lower median body mass index (BMI) (21.0 vs 24.2 kg/m2, p<0.001), higher mean log viral load (5.0 vs 4.9 copies/ml, p<0.001) and were significantly older (median age: 35 vs. 32 years, p<0.001). Men had higher mortality rates compared to women, 6.7 per 100 person-years (p-y), (95% CI: 5.8-7.8) vs. 4.4 per 100 p-y, (95% CI: 3.8-5.0); mortality rate ratio: 1.54, (95% CI: 1.27-1.87), p <0.001. Age-standardised mortality rate was 7.9 per 100 p-y (95% CI: 4.1-11.7) for men and 5.7 per 100 p-y (95% CI: 2.7 to 8.6) for women (standardised mortality ratio: 1.38 (1.15 to 1.70)). Mean CD4+ cell count increases post-ART initiation were lower in men at all follow-up time points. Men presented later in the course of their HIV disease for ART initiation with more advanced disease and experienced a higher mortality rate compared to women.

High incidence and persistence of hepatitis B virus infection in individuals receiving HIV care in KwaZulu-Natal, South Africa

Background

Hepatitis B virus (HBV), Human Immunodeficiency virus (HIV) and Tuberculosis (TB) are common infections in South Africa. We utilized the opportunity of care provision for HIV-TB co-infected patients to better understand the relationship between these coinfections, determine the magnitude of the problem, and identify risk factors for HBV infection in HIV infected patients with and without TB in KwaZulu-Natal, South Africa.

Methods

This retrospective cohort analysis was undertaken in 2018. In-care HIV infected patients were included in the analysis. Results from clinical records were analysed to determine the prevalence, incidence, persistence and factors associated with HBsAg positivity in HIV-infected patients with or without TB co-infection.

Results

A total of 4292 HIV-infected patients with a mean age of 34.7 years (SD: 8.8) were included. Based on HBsAg positivity, the prevalence of HBV was 8.5% (363/4292) [95% confidence interval (CI): 7.7–9.3] at baseline and 9.4% (95%CI: 8.6–10.3%) at end of follow-up. The HBV incidence rate was 2.1/100 person-years (p-y). Risk of incident HBV infection was two-fold higher among male patients (HR 2.11; 95% CI: 1.14–3.92), while severe immunosuppression was associated with a greater than two-fold higher risk of persistent infection (adjusted risk ratio (RR) 2.54; 95% CI 1.06–6.14; p = 0.004. Additionally, active TB at enrolment was associated with a two-fold higher risk of incident HBV infection (aHR 2.38; 95% CI: 0.77–7.35).

Conclusion

The provision of HIV care and treatment in high HBV burden settings provide a missed opportunity for HBV screening, immunization and care provision.

COVID-19 vaccines and the pandemic: lessons learnt for other neglected diseases and future threats

Through the experiences gained by accelerating new vaccines for both Ebola virus infection and COVID-19 in a public health emergency, vaccine development has benefited from a 'multiple shots on goal' approach to new vaccine targets. This approach embraces simultaneous development of candidates with differing technologies, including, when feasible, vesicular stomatitis virus or adenovirus vectors, messenger RNA (mRNA), whole inactivated virus, nanoparticle and recombinant protein technologies, which led to multiple effective COVID-19 vaccines. The challenge of COVID-19 vaccine inequity, as COVID-19 spread globally, created a situation where cutting-edge mRNA technologies were preferentially supplied by multinational pharmaceutical companies to high-income countries while low and middle-income countries (LMICs) were pushed to the back of the queue and relied more heavily on adenoviral vector, inactivated virus and recombinant protein vaccines. To prevent this from occurring in future pandemics, it is essential to expand the scale-up capacity for both traditional and new vaccine technologies at individual or simultaneous hubs in LMICs. In parallel, a process of tech transfer of new technologies to LMIC producers needs to be facilitated and funded, while building LMIC national regulatory capacity, with the aim of several reaching 'stringent regulator' status. Access to doses is an essential start but is not sufficient, as healthcare infrastructure for vaccination and combating dangerous antivaccine programmes both require support. Finally, there is urgency to establish an international framework through a United Nations Pandemic Treaty to promote, support and harmonise a more robust, coordinated and effective global response.

Oral mucosal lesions and HIV status in a rural household survey in South Africa

Several studies have documented the relevance of oral lesions in HIV populations. Oral HIV lesions are also considered useful indicators in HIV therapy. The objectives of the present study were to determine the prevalence of oral mucosal lesions (OML) in a rural population and to determine the differences, if any, in the prevalence of oral mucosal lesions of persons infected with HIV and persons not infected with HIV. The study was part of the Vaccine Preparedness Study (VPS) conducted by the Medical Research Council in Hlabisa, KwaZulu Natal, South Africa between 2000 and 2002.

METHODS

A cross-sectional household survey examined adults aged 15 to 50 years. Oral mucosal lesions were determined by a presumptive diagnosis. Informed consent was obtained for the oral examination and separately for collecting a blood sample to determine HIV status by ELISA.

RESULTS

A total of 2313 adults were interviewed for the VPS. Oral mucosal lesions were assessed in a sample comprising 537 adults. Of these, 185 consented to HIV testing and 22.7% (95% Confidence Interval (CI): 16.9-29.4%) were HIV positive. The prevalence of oral mucosal lesions in the total sample was 12.8% (95% CI: 10-16.3%). The prevalence of OML was 21.4% (9/42) among those who consented to a blood test and were HIV positive and 9.8% (n = 14/143) among those who were HIV negative.

CONCLUSION

The prevalence of OML among HIV positive participants was significantly higher than among HIV negative participants.